How to tell if Blender has crashed?
If the interface is still responsive, Blender hasn't crashed (yet). But in this case is engaged on some heavy computing.

In this case the issue is that you are trying to render using an insane number of samples!

You've set up 1000 samples but have the square samples box enabled, that will make the number 1,000,000 (1000 samples x 1000). 



A million samples will require massive computing power!

Uncheck the square samples box and bring the number of samples to a reasonable number...